/Engine/Plugins/Online/OnlineSubsystemUtils/Source/OnlineSubsystemUtils/Public/PartyBeaconHost.h
Handle a reservation cancellation request received from an incoming client
virtual void ProcessCancelReservationRequest ( [APartyBeaconClient](API\Plugins\OnlineSubsystemUtils\APartyBeaconClient) * Client, const [FUniqueNetIdRepl](API\Runtime\Engine\GameFramework\FUniqueNetIdRepl) & PartyLeader )